Porsche Group B 930 Project

The Specifications

In 1982, FISA (the governing body for sports car racing for the FIA) changed to a 3 group format (A,B,C).

Group A for production touring cars with at least four seats, a minimum yearly production of 5,000 units and a minimum weight based on the engine's capacity.

Group B for two seat GT cars with a minimum yearly production of 200 units and a minimum weight based on the engine's capacity.

Group C for prototypes with a minimum weight of 800 kg (later increased to 850 kg) and a set of minimum and maximum dimensions.  Engine type and size are free, power being governed solely by the allowance of 100 octane petrol for the race distance.

Porsche 956 dominating Group C competition

Group C allowed manufacturers to create race specific prototypes similar to the golden era of sports racing in the late 60s and early 70s.  Porsche's 956 (and later, the IMSA compliant 962) dominated group C, but there was no real factory attention focused to Group B.  As a stop gap measure, Porsche decided to build 6 cars at the beginning of 1983 based on it's homologated 911 Turbo (Type 930) to compete against BMW's onslaught of M1s.  All 6 cars were entered in the 24 Hours of Le Mans with 4 finishing the race, one winning the Group B category and finishing 11th overall.

  Fast Castrol M1 - Early M1 competing in Group B - Porsche 930 pit next to BMW M1 pit

The Group B 930 suffered a severe weight handicap because the displacement of it's 3.3 liter turbo charged engine had to multiplied by 1.4 (40% increase) which put the car in the 5 litter category (1,235 kg minimum weight).  It's slightly modified engine (strictly regulated by Group B specifications) produced a little over 360 HPs that were put on the terra perma using 9.5 inch front wheels and 11 inch back wheels.   Regulations would not allow wheels to protrude beyond the standard fenders.   Although the car was starved for traction, driver Paul Smith commented on how much fun the 930 was to drive because the tail could be hung out at an "impossible angle".

Charles Ivery 930 at Monza - Georg Memminger 930 at Imola

Engine modifications were few.  A larger intercooler, longer duration cam (cam height changes were not permitted), and increased boost (standard - 0.8 BAR; Group B - 1.0 to 1.4 BAR) were the only changes made to the 930 engine.

Suspension modification were allowed as long the the original suspension mount points where not altered.  Solid mount points and strut tower braces were permitted.   Coil over springs were not permitted, but torsion bars size was not regulated.   Porsche used 22mm torsion bars in the front and 28 mm torsion bars in the rear.   The anti-sway bars were of standard 911 design (solid-through chassis) and were 22mm in front and 18 mm in the rear.

Wheels were 9.5X16 in front and 11X16 in the rear with Dunlop tires (245/575-16 and 300/625-16).  The oil cooler was mounted in the front with the reservoir mounted in the front boot.  The cars were stripped with full roll cages.

Unfortunately by 1984, it was obvious that there was little popularity for anything other than Group C racing and FIA decided to drop the category at the end of the 1984 season.  With no place left to race other than IMSA, where the 934 still dominated, the 930 was retired to historic and club racing.

The Car